A method for preparing a platinum target

Abstract

The present invention relates to the field of semiconductor technology, and specifically to a method for preparing a platinum target. The method comprises the following steps: step 1, taking a platinum powder raw material and placing it in a sheath, vacuumizing it and then welding it; step 2, hot isostatic pressing and sintering the sheath after welding and sealing it in step 1; step 3, forging and pressing the sheath after treatment in step 2, and then performing a first annealing treatment; step 4, removing the sheath from the platinum material after the first annealing treatment, and then performing a rolling treatment and a second annealing treatment; step 5, processing it into a platinum target material after the second annealing treatment. The preparation method uses a powder metallurgy method, vacuuming the material, and then performing a hot isostatic pressing and sintering treatment, which effectively reduces the forming temperature and saves energy consumption; at the same time, by wrapping the platinum target material in a sheath and forging it, cracks and oxidation problems can be avoided, platinum material waste can be reduced, and raw materials can be saved; after forging, the grain size is well controlled by rolling treatment, which improves the density. The entire preparation process is low-cost and easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a platinum target material. Background Art

[0002] The rapid development of new devices and materials in the microelectronics industry has led to widespread application of electronic, magnetic, optical, optoelectronic, and superconducting thin films in high-tech and industrial fields, driving the growing market for sputtering targets. The sputtering deposition performance of a target is influenced by factors such as its density, purity, grain size and size distribution, grain orientation, and texture. Taking grain size and size distribution as an example, targets with finer grains exhibit faster sputtering rates than targets with coarser grains. This is because smaller grains have more high-free-energy, high-atomic-dislocation grain boundaries, making them more susceptible to plasma bombardment during magnetron sputtering. Consequently, targets with smaller grain sizes exhibit higher sputtering deposition rates than larger targets. Furthermore, targets with smaller grain size variations produce more uniform thickness distribution in the deposited films. Maintaining grain size variation within 20% significantly improves the quality of the films produced by sputtering.

[0003] The grain size of different materials has different effects on the sputtering deposition performance of the target material, and the grain refinement process of different materials is also different. Even for the same material, the refinement process varies greatly depending on the purpose. The conventional preparation method of platinum targets used in the semiconductor field is vacuum melting and then forming. The vacuum melting temperature is as high as 1700°C, the cost is also increased accordingly, and the grains are easy to grow. At present, there are few studies on the process of grain control and density of platinum targets. How to control the grain of platinum targets and improve the density of platinum targets is a problem that technicians in this field need to solve. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a platinum target material which can reduce the molding temperature and save costs while avoiding cracks and oxidation problems, controlling the grain size and improving the density.

[0005] Based on the above objectives, the present invention adopts the following technical solutions:

[0006] A method for preparing a platinum target comprises the following steps:

[0007] Step 1: Place platinum powder raw material into a bag, evacuate the bag, and seal it with welding;

[0008] Step 2, hot isostatic pressing and sintering the package sealed in step 1;

[0009] Step 3, forging the sleeve processed in step 2, and then performing a first annealing process;

[0010] Step 4, after removing the sheath from the platinum material subjected to the first annealing treatment, rolling the material and then subjecting it to a second annealing treatment;

[0011] Step 5: After the second annealing treatment, the target is processed into a platinum target.

[0012] Preferably, in step 1, the diameter of the sheath is 80 to 150 mm, and the thickness is 45 to 135 mm.

[0013] Preferably, in step 2, the hot isostatic pressing sintering treatment is performed at a temperature of 1050-1250° C., a pressure of 140-200 MPa, and a heat preservation time of 60-180 min.

[0014] Preferably, the initial temperature of the forging process in step 3 is not lower than 900° C., the end temperature is not lower than 300° C., and the diameter after forging is 108 to 200 mm and the thickness is 13 to 38 mm.

[0015] Preferably, the first annealing treatment temperature in step 3 is 750-900° C., and the heat preservation time is 60-120 minutes.

[0016] Preferably, the rolling temperature in step 4 is 300-500° C., the diameter after rolling is 160-300 mm, and the thickness is 5-15 mm.

[0017] Preferably, the second annealing treatment temperature in step 4 is 700-850° C., and the heat preservation time is 60-120 minutes.

[0018] Preferably, the platinum powder raw material in step 1 is platinum powder with a purity of 4N or above.

[0019] Preferably, the obtained platinum target has a purity of at least 4N, an oxygen content of less than 50 ppm, and an average grain size of less than 100 μm.

[0020] Preferably, the forging treatment in step 3 is performed multiple times in the height direction; and the rolling in step 4 is performed alternately in the vertical and horizontal directions after removing the sheath of the platinum material.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The preparation method of the platinum target provided by the present invention uses a powder metallurgy method to perform a vacuum treatment to extract air, water vapor and impurities from a sheath, and then performs a hot isostatic pressing sintering treatment, thereby effectively reducing the forming temperature from above 1800°C to 1050-1250°C, thereby saving energy consumption. At the same time, the platinum target is wrapped in the sheath for forging, thereby avoiding the generation of cracks and oxidation problems, reducing platinum metal waste and saving raw materials. After forging, the grain size is well controlled by rolling treatment, thereby improving the density. The entire preparation process is low-cost, easy to operate, and effectively controls the grain size of the platinum target.

[0023] Forging is a processing method that uses a forging machine to apply pressure to a metal blank to cause it to undergo plastic deformation to obtain a forging with certain mechanical properties, a certain shape and size. Rolling is a pressure processing method in which a metal blank is passed through the gap between a pair of rotating rollers (of various shapes), where the material cross-section is reduced and the length is increased due to the compression of the rollers. Forging is a plastic deformation in the vertical direction of height, while rolling is a plastic deformation in the horizontal direction. The preparation method of the present invention, by first performing a forging process in the vertical direction, and then removing the sheath and rolling alternately in the vertical and horizontal directions, can further control the grain size, making it difficult for the grains to grow, while also improving the density of the overall platinum target material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope photograph of the platinum target obtained in Example 1 of the present invention;

[0025] Figure 2 This is a grain size distribution diagram of the platinum target obtained in Example 1 of the present invention;

[0026] Figure 3 This is a photo of the platinum target obtained in Example 2 of the present invention;

[0027] Figure 4 This is a grain size distribution diagram of the platinum target obtained in Example 2 of the present invention;

[0028] Figure 5 This is a photo of the platinum target obtained in Example 3 of the present invention;

[0029] Figure 6 This is a grain size distribution diagram of the platinum target obtained in Example 3 of the present invention; DETAILED DESCRIPTION

[0030] Refer to the following Figures 1 to 6 To describe a method for preparing a platinum target material according to an embodiment of the present invention. In the description of this embodiment, it should be understood that the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0031] In the description of the present embodiment, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in any one or more embodiments or examples.

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described in detail below. However, the following embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without making any creative work are within the scope of protection of the present invention.

[0033] The present invention provides a method for preparing a platinum target, comprising the following steps:

[0034] Step 1: Place platinum powder raw material into a bag, evacuate the bag, and seal it with welding;

[0035] Step 2, hot isostatic pressing and sintering the package sealed in step 1;

[0036] Step 3, forging the sleeve processed in step 2, and then performing a first annealing process;

[0037] Step 4, after removing the sheath from the platinum material subjected to the first annealing treatment, rolling the material and then subjecting it to a second annealing treatment;

[0038] Step 5: After the second annealing treatment, the target is processed into a platinum target.

[0039] Preferably, in step 1, the diameter of the sheath is 80 to 150 mm, and the thickness is 45 to 135 mm.

[0040] Preferably, in step 2, the hot isostatic pressing sintering treatment is performed at a temperature of 1050-1250° C., a pressure of 140-200 MPa, and a heat preservation time of 60-180 min.

[0041] Preferably, the initial temperature of the forging process in step 3 is not lower than 900° C., the end temperature is not lower than 300° C., and the diameter after forging is 108 to 200 mm and the thickness is 13 to 38 mm.

[0042] Preferably, the first annealing treatment temperature in step 3 is 750-900° C., and the heat preservation time is 60-120 minutes.

[0043] Preferably, the rolling temperature in step 4 is 300-500° C., the diameter after rolling is 160-300 mm, and the thickness is 5-15 mm.

[0044] Preferably, the second annealing treatment temperature in step 4 is 700-850° C., and the heat preservation time is 60-120 minutes.

[0045] Preferably, the platinum powder raw material in step 1 is platinum powder with a purity of 4N or above.

[0046] Preferably, the obtained platinum target has a purity of at least 4N, an oxygen content of less than 50 ppm, and an average grain size of less than 100 μm.

[0047] Example 1

[0048] A method for preparing a platinum target comprises the following steps:

[0049] Step 1: Platinum powder with a purity of 4N or higher is placed in a steel ladle, compacted and vacuumed, and then sealed by welding; wherein the ladle has a diameter of 110 mm and a thickness of 80 mm;

[0050] Step 2: hot isostatic pressing (HSP) the sealed package from step 1. The HSP is performed at a temperature of 1150° C., a pressure of 170 MPa, and a holding time of 120 minutes.

[0051] Step 3, forging the sheath after step 2, and then performing a first annealing treatment; wherein the initial temperature of the forging process is not less than 900°C, and the end temperature is not less than 300°C. After forging, the sheath has a diameter of 150 mm and a thickness of 25 μm; the first annealing temperature is 820°C, and the temperature is kept at this temperature for 90 minutes;

[0052] In step 4, the platinum material after the first annealing treatment is removed from the sheath, rolled, and then annealed for a second time; wherein the rolling temperature is 400° C., and the diameter of the platinum material after rolling is 240 mm and the thickness is 10 mm; the second annealing treatment temperature in step 4 is 780° C. and the temperature is kept at this temperature for 90 minutes.

[0053] Step 5: After the second annealing treatment, the target is further processed into a platinum target. The purity of the obtained platinum target is at least 4N and the oxygen content is 38 ppm.

[0054] like Figure 1 、 Figure 2 As shown, the maximum grain size of the platinum target obtained in Example 1 is 170.05 μm, the minimum grain size is 34.51 μm, and the average grain size is 78.5 μm.

[0055] Example 2

[0056] A method for preparing a platinum target comprises the following steps:

[0057] Step 1: Platinum powder with a purity of 4N or higher is placed in a steel ladle, compacted and vacuumed, and then sealed with a weld; wherein the ladle has a diameter of 80 mm and a thickness of 45 mm;

[0058] Step 2: hot isostatic pressing (HSP) the sealed package from step 1; wherein the HSP is performed at a temperature of 1050° C., a pressure of 200 MPa, and a holding time of 60 minutes;

[0059] Step 3, forging the sheath after step 2, and then performing a first annealing treatment; wherein the initial temperature of the forging process is not less than 900°C, and the end temperature is not less than 300°C. After forging, the sheath has a diameter of 108 mm and a thickness of 13 mm; the first annealing temperature is 900°C, and the temperature is kept for 60 minutes;

[0060] In step 4, the platinum material after the first annealing treatment is removed from the sheath, rolled, and then annealed for the second time; wherein the rolling temperature is 300° C., and the diameter of the platinum material after rolling is 160 mm and the thickness is 5 mm; the second annealing temperature in step 4 is 700° C. and the temperature is kept at this temperature for 120 minutes.

[0061] Step 5: After the second annealing treatment, the target is further processed into a platinum target. The purity of the obtained platinum target is at least 4N and the oxygen content is 35 ppm.

[0062] like Figure 3 、 Figure 4 As shown, the maximum grain size of the platinum target obtained in Example 2 is 172.1 μm, the minimum grain size is 36.8 μm, and the average grain size is 86.5 μm.

[0063] Example 3

[0064] A method for preparing a platinum target comprises the following steps:

[0065] Step 1: Platinum powder with a purity of 4N or higher is placed in a steel ladle, compacted and vacuumed, and then sealed by welding; wherein the ladle has a diameter of 150 mm and a thickness of 135 mm;

[0066] Step 2: hot isostatic pressing (HSP) the sealed sleeve from step 1. The HSP is performed at a temperature of 1250° C., a pressure of 140 MPa, and a holding time of 180 minutes.

[0067] Step 3, forging the sheath after step 2, and then performing a first annealing treatment; wherein the initial temperature of the forging process is not less than 900°C, and the end temperature is not less than 300°C. After forging, the sheath has a diameter of 200 mm and a thickness of 38 mm; the first annealing temperature is 750°C, and the temperature is kept at this temperature for 120 minutes;

[0068] In step 4, the platinum material after the first annealing treatment is removed from the sheath, and then rolled and then annealed for the second time; wherein the rolling temperature is 500° C., and the diameter of the platinum material after rolling is 300 mm and the thickness is 15 mm; the second annealing temperature in step 4 is 850° C. and the temperature is kept for 60 minutes.

[0069] Step 5: After the second annealing treatment, further processing is performed to form a platinum target. The purity of the obtained platinum target is at least 4N and the oxygen content is less than 40 ppm.

[0070] like Figure 5 、 Figure 6 As shown, the maximum grain size of the platinum target obtained in Example 3 is 169.1 μm, the minimum grain size is 37.2 μm, and the average grain size is 84.8 μm.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a platinum target, characterized in that: The following steps are involved: Step 1: Place platinum powder raw material into a bag, evacuate the bag, and seal it with welding; Step 2, hot isostatic pressing and sintering the package sealed in step 1; Step 3, forging the sleeve processed in step 2, and then performing a first annealing process; Step 4, after removing the sheath from the platinum material subjected to the first annealing treatment, rolling the material and then subjecting it to a second annealing treatment; Step 5: After the second annealing treatment, the target is processed into a platinum target; In step 2, the hot isostatic pressing sintering treatment is performed at a temperature of 1050-1250° C., a pressure of 140-200 MPa, and a holding time of 60-180 minutes; The average grain size of the obtained platinum target is less than 100 μm.

2. The method for preparing a platinum target according to claim 1, wherein: In step 1, the diameter of the sheath is 80 to 150 mm, and the thickness is 45 to 135 mm.

3. The method for preparing a platinum target according to claim 1, wherein: In step 3, the initial temperature of the forging process is not lower than 900° C., and the ending temperature is not lower than 300° C. The diameter after forging is 108 to 200 mm, and the thickness is 13 to 38 mm.

4. The method for preparing a platinum target according to claim 1, wherein: In step 3, the first annealing treatment temperature is 750-900° C. and the heat preservation time is 60-120 minutes.

5. The method for preparing a platinum target according to claim 1, wherein: In step 4, the rolling temperature is 300-500° C., the diameter after rolling is 160-300 mm, and the thickness is 5-15 mm.

6. The method for preparing a platinum target according to claim 1, wherein: The second annealing treatment temperature in step 4 is 700-850° C. and the heat preservation time is 60-120 minutes.

7. The method for preparing a platinum target according to claim 1, wherein: The platinum powder raw material in step 1 is platinum powder with a purity of 4N or above.

8. The method for preparing a platinum target according to claim 1, wherein: The obtained platinum target has a purity of at least 4N and an oxygen content of less than 50 ppm.

9. The method for preparing a platinum target according to claim 1, wherein: The forging process in step 3 is to perform multiple forging processes in the height direction; and the rolling in step 4 is to remove the sheath of the platinum material and then perform alternating rolling in the vertical and horizontal directions.

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